We all have a functioning style. We all have a way in which we tend to experience and perceive, a way in which we feel, think and behave. When the pattern becomes unhealthy and rigid, it is likely a personality disorder. It is unhealthy because we no longer have the freedom to chose, we make choices based on a rigid behavior or inflexible emotional and thought pattern. There are many specific types of personality disorders, such as borderline PD, obsessive PD, avoidant PD and many others.